V. Server Programming

This part is about extending the server functionality with
user-defined functions, data types, triggers, etc. These are
advanced topics which should probably be approached only
after all the other user documentation about PostgreSQL has been understood. This
part also describes the server-side programming languages
available in the PostgreSQL
distribution as well as general issues concerning server-side
programming languages. This information is only useful to
readers that have read at least the first few chapters of
this part.